Detailed examination of HLA antibody development on renal allograft failure and function

This is a long-term retrospective case-control study. Serial sera were collected over 17 years (1991-2008) from two groups comprised of 29 patients with allograft failure (250 sera) and 25 controls with functioning grafts (305 sera), each control matched by transplant date to one failure-group patient, and all patients tested with single antigen beads. The median follow-up for failure-group patients was 7.3 +/- 4.7 years and 11.8 +/- 4.4 years for controls. HLA alloantibodies appeared in 28 of the 29 failure-group patients (97%) and in 12 of the 25 controls (48%) (p < 0.0001). DSA and non-DSA that appeared alone--without any DSA detected-were both associated with graft failure (p = 0.001, p = 0.01). DSA against HLA-DQ antigen was found in 13 of 17 graft-failed patients who had received DQ-incompatible transplants (76%) compared with only one of 11 similarly DQ-mismatched control patients (9%) (p < 0.001). The strength of strong DSA (defined as MFI > 5000) was higher in graft-failed patients than in graft-functioning patients. The time it took for antibodies to develop also differed between groups. HLA antibodies were formed sooner in the failure group compared with the controls (1.7 versus 3.7 years, P < 0.01). Fifteen of the failure group patients developed antibodies within one year while none in the control group did. In conclusion, our study reinforces the observation that circulating de novo HLA alloantibodies predict adverse long-term kidney allograft outcomes. The significant negative impact of all alloantibodies calls for clinicians to monitor patients and implement removal therapy when alloantibody is first detected. This may prove a key step in the ongoing attempt to prevent chronic rejection and prolonging renal allograft survival.